Atsushi Nakanishi1, Issei Fukunaga2,3, Masaaki Hori2, Yoshitaka Masutani4, Hattori Takaaki5, Masakazu Miyajima6, Shigeki Aoki2. 1. Department of Radiology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. naka24@juntendo.ac.jp. 2. Department of Radiology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. 3. Department of Health Science, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa, Tokyo, 116-8551, Japan. 4. Division of Radiology and Biomedical Engineering, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. 5. Department of Neurology and Neurological Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan. 6. Department of Neurosurgery, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
Abstract
INTRODUCTION: The goals of this study were to examine the usefulness of diffusional kurtosis imaging (DKI) for assessing microstructural changes in the compressed corticospinal tract (CST) among patients with idiopathic normal pressure hydrocephalus (iNPH). METHODS: Eleven patients with iNPH (mean age: 73.6 years, range: 65-84), who underwent 3-T magnetic resonance imaging, including DKI before surgery, were recruited. Six age-matched, healthy subjects (mean age: 69.8 years, range: 60-75) served as the control group. DKI and diffusion tensor imaging parameters were calculated and compared between the iNPH and the control groups using tract-specific analysis of the CST at the level of the lateral ventricle. RESULTS: Mean diffusional kurtosis (DK) and axial diffusion kurtosis were significantly lower in iNPH patients. However, apparent diffusion coefficient, fractional anisotropy, and axial eigenvalue (λ₁) were significantly higher in the iNPH group than in the control group. CONCLUSIONS: The mechanical pressure caused by ventricular enlargement in iNPH patients might induce formation of well-aligned fiber tracts and increased fiber density in the CST, resulting in decreased DK. DKI is able to depict both the altered microstructure and water molecule movement within neural axons and intra- or extracellular space. In addition, the investigated DKI parameters provide different information about white matter relative to conventional diffusional metrics for iNPH.
INTRODUCTION: The goals of this study were to examine the usefulness of diffusional kurtosis imaging (DKI) for assessing microstructural changes in the compressed corticospinal tract (CST) among patients with idiopathic normal pressure hydrocephalus (iNPH). METHODS: Eleven patients with iNPH (mean age: 73.6 years, range: 65-84), who underwent 3-T magnetic resonance imaging, including DKI before surgery, were recruited. Six age-matched, healthy subjects (mean age: 69.8 years, range: 60-75) served as the control group. DKI and diffusion tensor imaging parameters were calculated and compared between the iNPH and the control groups using tract-specific analysis of the CST at the level of the lateral ventricle. RESULTS: Mean diffusional kurtosis (DK) and axial diffusion kurtosis were significantly lower in iNPH patients. However, apparent diffusion coefficient, fractional anisotropy, and axial eigenvalue (λ₁) were significantly higher in the iNPH group than in the control group. CONCLUSIONS: The mechanical pressure caused by ventricular enlargement in iNPH patients might induce formation of well-aligned fiber tracts and increased fiber density in the CST, resulting in decreased DK. DKI is able to depict both the altered microstructure and water molecule movement within neural axons and intra- or extracellular space. In addition, the investigated DKI parameters provide different information about white matter relative to conventional diffusional metrics for iNPH.
Authors: Anthony Marmarou; Harold F Young; Gunes A Aygok; Satoshi Sawauchi; Osamu Tsuji; Takuji Yamamoto; Jana Dunbar Journal: J Neurosurg Date: 2005-06 Impact factor: 5.115
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